Rotary machine



3 SHEETS-SHEET I.

Patented Dec. 28; 1920.

E WITTIG ROTARY MACHINE.

APPLICATION FILED OCT. 2a, 1915.

Tim--1- E. WITTIG.. ROTARY MACHINE.

APPLlCATiON HLED 0CT.26, I915.

Patented Dec. 28,1920 3 SHEETS-SHEET 2- x6 1/? I /7/4 z 2 a Y UNITEDSTATES PATENT orrlce.

EMIL WITTIG, 0F BASEL, SWITZERLAND.

' ROTARY MACHINE.

Specification of Letters Patent. Patented D 28 "1920 Application filedoctober 26, 1915. Serial No. 57,929.

.- exact specification.

The present invention relates to improvements in rotary machines havinga rotary drum arranged in a cylindrical or substantially cylindricalcasing, said drum being provided with radially movable pistons andeccentrically supported in its casing to form therein a crescent-shapedworking chamber, subdivided by the pistons in a plurality of cells.

In this kind of machines, which are applicable as air pumps (compressorsand vacuum pumps) as well as motors and which generally work with a highspeed it is necessary to have a correct mechanical working of theslidable pistons in the slots of the piston drum and against-the wallsof the casing. One object of the present invention is to compensate orcounteract the friction of the sliding pistonsin their slots, tocorrectly lubricate the pistons from the inner part of their guidingslots and-to eliminate any unilateral forces'which would increase thefriction of the pistons on the inner wall of the casing.

Rotary machines with a great number of revolving pistons have theadvantage. that simple openings in the wall of the casing may sufiicefor the inlet and outlet of the working fluid, such as air, steam'andthe like, and the present invention particularly relates to machines ofthis kind, without, however, possessing the disadvantages of priormachines:

The accompanying drawings represent an embodiment of the presentinvention.

Figure l is a transverse section ofa'rotary machine provided withcertain improvements according to the invention and which is capable ofworking as motor or as pump.

Fig. 2 is a partial longitudinal section thereof; 7

Fig. 8 is a transverse section on the line AB of Fig. 2;

Fig. 4 is a longitudinalsection of a rotary machine of the multipletype;

Fig. 5 is a partial longitudinal section of a modification of such amultiple machine;

Fig. 6 is a partial longitudinal section, similar to Fig. 2.

Fig. 7 is a sectional view (with rotor removed) on line 77, F 9;

Fig. 8 is a sectional View (with rotor removed) on line 8-9, Fig. 7,looking in the direction of the upwardly pointing arrows;

Fig. 9 is a View similar to Fig. '8, looking in the direction ofthedownwardly pointing arrows.

Beferring first to Figs. 1., t2 and 3, the cylindrical casing a inclosesthe eccentrically arranged rotary piston drum b provided with a greatnumber of slidable pistons 0 arranged in radial slots ofthe drum. The

pistons 0 separate or divide the crescentshaped working chamber withinthe casing a into' a great number of'cells a. When the machine isdesigned to work as .a motor with steam or the like, the driving fluidis ad.- mitted through the pipe (Z into an admission chamber (Z andflows therefrom into such cells 2 that are freely open to said chamber.In Fig. lthis would be the cells marked 2 In the cells 2 there takesplace the expansion of the fluid with Working, while the cells at 2discharge the expanded fluid into the exhaust chamber 6 connected'to theexhaust pipe 6. 7 These operations take place successively in each cellduring one revolu- -tion of the drum.

As the pressure of the steam acts not only upon the great side faces ofthe pistons, but also upon the outer longitudinal edges, that is thesurfaces of the pistons which contact with the inner wall of the casing,it has been .proposed to provide inthe end plates of the ing there theinner slot spaces of the drum with the exhaust chamber 6 In the Zonewhere the expansion takes place,'that is in the zoneof the working cells2 not only the capacity of said cells increases, but also that of theslot spaces belonging to the corresponding pistons; if consequently thesaid slot spaces haveprevimeans of the channels f as the cells and thecommunication between the slot spaces and ously been put under the samepressure by the channels has been closed, there will take place thereina similar expansion of the fluid, so that a pressure compensation rela-'tively to the longitudinal edges of the pistons will be also insuredcompletely or nearly during the period of expansion of the operation- 5Now, the pistons which are in the zone of expansion are exposed to" aconsiderable friction in their slots, as there are different pressureson their opposite sides. The pistons 'at that place may not so easily bemoved outwardly their slots as the pistonsin the admission zone. Thisunlikeness of the friction of the pistons in their slots is obviatedaccording to the present invention by the fact that the pressurecompensation channels it are prolonged to, such an extent as to beconnected also with one or more inner slot'spaces which'are alreadywithin the expansion'zone. By these means,

not only the pistons belonging to saidfslot spaces are easily movedoutwardly, but in all slot spaces within the zone of expansion, theexpansion of the admitted fluid will not have progressed to thesamedegree as in the corresponding working cells 2 so that there is alwaysin each slot space a greater pressure than in the corresponding cell,which "efficiently counteracts the frictional forces.

' As in starting the machine there are no centrifugal forces that drivethe pistons out ward ly, the machine would not startautomatically,According to another improvement, the pipe branch'g is connected to theadmission pipe at rearward of a regulating valve 19 in pipe d. When themachine is to bestarted, steam is first admitted through said pipebranch 9, the'valve 10 being closed, whereby the pistons c in theadmission and in the expansion zone are pushed outward;

after this operation, the valve 1) is opened,

in successivesteps in accordance with the increase of the speed ofrotation and-the consequent increase of the centrifugal forces of thepistons 0.

provement consistsin the use, for the starting operation, of a valvecontrolledby-pass I steam pipe 9 connectedwith a'channel f toallowadmission of steam to the inner slot space of one or morepistons in theexpansion-zone, while the valve 9 in the pipe branch 9 is closed,so'that thepistons within the reach of the channels f are pre viouslynot pushed outward and thus .do not interfere with the admission ofsteam The machinecould not start in this way with the full or increasedtorque, as at the. beginning of the starting operation there would notbe any steam in the working cells 2 so that, the latter-could not efii-'ciently work. In this respect, another imlubricate the sliding parts ofsuch machines,

especially the pistons in the slots of the revolving drum. Oil used forthis purpose has, -of course, the tendency to traveling outward by theaction of the centrifugal forces, anddoes not reach the innermost partsof the piston guide-slots if it is not forcibly introduced thereinto;but this .introducti'o n of oil into the slots is very diflicnlt inconstructions where the slots have a considerable. axial length.According to another improvement, the steam current ad-- mitted by thepipe 9, orgby the pipe 9 or by both of. said pipes to the inner slotparts of certain pistons for friction compensation purposes is at-thesame time .used as a conveyer for oil, which is admitted thereto by anoil tube h connected'for example to the pipe 9, said oil being thusdistributed through the whole space of the inner slot parts and allowedto flow outward along the-piston surfaces by the action of thecentrifugal forces to amply lubricate'said surfaces over their wholeextent.

It is advantageous to arrange the lateral channels 7, f with such alength that each communicates with only a small group of piston slots,so as to give rise to a low pressure in the lattenwhen they come'withinthe reach of said channels. The working fluid,-then flowing' into theslot spaces under pressure inducesa violent current therein,

which conveys the oil far intosaid spaces.

()bviously, such short channels or recesses may be provided alternatelyOnb th front walls 'of the machine, so that an oil charged current is'first introduced into the slot space from a one front side, conveyingthe o1l faithrough said space, andthen in further rotation another oilcharged current from the other front side.

'F or supporting and counterbalancing the centrifugal forces ofthe'pistons, it is old to use rotating balance rings 2' (Figs. 2 and 3)freely adjustable upon the outer periphcry. of the pistons (eveiituallythrough intervening sliding, shoes) and carried along with the revolvingpistons. The inner wall of the casing insures only the circular guidingof the outer piston ends, it does notsupport at 2.11--o1-' n1y to asmall degree the centrifugal forces of the sliding pistons; The balancerings 2' have on their outer sides apluralityof confined pressureperipheral wall of the casing is not sub-- jected to pressure at all bythe pistons owing to thedifference in' the degree of projection of thepistons from their guide slots during rotation. c

It results therefrom that the pistons have the tendency to exert aresulting pressure upon one side upon the casing. This should notnecessarily be injurious, if this tighter bearing of the pistons uponthe inner wall of the casing'were obtained on the advantageous side. Atthe side where in" air pumps the compression and motors the expansiontakes place, it is desirable to have a tight joint between the pistonsand the wall of the casing, in orderto obviate losses by leakage. Thisis still more desirablein the zone of the smallest capacity of thecells, as a rapid variation of pressure takes place in said zone over ashort part of the circumference in air pumps as well as in motors; forexample, in the machine Y represented by Figs. 1, 2 and 3 the end of theexhaust chamber e is'only a small distance from the beginning of theadmission chamber al 'It has been found that most of the resultingforces not supported by the balance rings tend'to strongly press thepistons against the wall of the casing in the zone of the greatest cellcapacity; for example, the greater centrifugal forces of the pistons insaid zone have the described tendency, and the frictional forces in theslots directed outwardly are also greatest in the zone, where thepistons project to their greatest extent. Now, in this zone, a tightjoint of the pistons would not be necessary;'

no injury would ensue if the pistons should be separated a little fromthe wall of the casing, as the difference of pressure on'the sides of apiston is here very small.

To insure. a tight joint of the pistons on the side where the cells havethe smallest capacity, an'additional force could be exerted upon thebalance rings and .clirected toward the said side. As the'balance ringsmust freelyadjust themselves, this additional force should be an elasticone and v could for example consist in the action of a weight or of aspring pressing by means of a roller upon the balance rings. If themachine is so arranged that the cells with final compression pressure.

aid in a favorable sense. But, in most cases,

all these means are insuflicient.

Now, I have obtained the same result,

but in a better way by the arrangement of an auxiliary pressure chamberZ on the outside of the balance rings 2', which is supplied with aconvenient fluid under pressure. By this means, the amount of theapplied additional force can at the same time be varied at will. In somemachines, the fluid under pressure to be supplied to said chamber Zmay-be tapped from the machine itself in an unvariable manner. For:example in compressors, as long as the working cells have not yetreached a distributing opening, the compression is alwaysthe sameandindependent of what .will be the It is therefore possible to connect inthis zone the pressure chamber Z by a channel m (Fig. 3) with one of thecells in said zone, the the chamber Z being thus supplied with constantpressure.

If a pressure chamber a. is arranged on the outside of the balance ringsin the zone of the smallest cell capacity, then I supply said chamberwith a lower pressure than that existing at that place .on the inside ofthe balance rings, the said pressure being taken by a channel 0 from thechamber e (inlet chamber for the operation of the machine as air pump).c

In a machine operating as air pump, the pressure chamber Z isadvantageously displaced somewhat toward the compression side, in orderthat the applied additional force may also compensate a part of thefrictional forcesof the pistons. Then the machine operates as motor, theefiect of this additional force is for the same reason displacedsomewhat toward the exhaust side. The direction of the said additionalforce will thus always deviate somewhat from the line of junctionbetween the places of thesmallest and the greatest cell capacity.

In the rotary machines shown in the drawings, indifferently whether theywork as pump or as motor, the cells in one half of the crescent-shapedwork chamber are generally under a higher pressure than that capacity inone elementary machine is on the same longitudinal line with the zone ofthe greatest cell capacity in the adjacent elementary machine. By thisarrangement,

' the pressures in the bearings in the parti vtion wall 9 arrangedbetween the elemen advantageousto substitute two low pressure units forone of the two units of greater capacity. 1 The said two low pressureunits are then of approximately the same I aggregate capacity as thehigh, pressure unit and the three units can be arranged in such a waythat the tranvers e bearing pressures'of the piston drums aresubstantially compensated ior. The construction according to Fig. 4 maycomply with these conditions; in this case, the middle elementarymachine would be of the high pressure type and'the two outer elementarymachines of the low pressure type.

As 1n machines coupled in the described manner the piston drums areheated to a higher degree than the-corresponding casings, resulting in aconsiderable'friction on the ends, it is advantageousto provide for alittle axial play between the drums and the casings; but with such aplay, the joint would give rise to leakages. To avoid losses byleakages, the construction may be modified according to-Fig. 5 whereinthe parts of the piston drums between the partition walls 9 have such athickness that the pistons, when in their outermost positions, havetheir inner edges projecting inward beyond the edges'of the bearingopenings in said walls 9. In other words, the piston drums of thedifferent units have connections and tighten-- ing parts, of the samediameter as the drum bodies located within the bearing openings ofthepartitio'n walls g. In this case, thepartitionwa'lls g areadvantageously so arranged that they are slightly movable perpendicularly to the axis of the drums, in order to be capable ofadjusting themselves in their housing. A spring r or the like may beprovided to support or compensate for the weight of the partition walls9.

What I claim is:' Y 4 1. In a rotary machine, a casing having sidewalls, a rotary drum arranged therein so as. to form a crescent-shapedworking chamber, numerous slidable pistons on said drum arranged todivide said chamber into a plurality of cells, said pistons beinglocated in substantially radial slots of the. drum; said parts beingarranged to provide a at least one piston within the intermediateworking zone, and a pipe connection for admitting fluid under pressureto said channel,"

substantially as and for the purpose described.

' 2. In a rotary machine, a casing having sidewalls, a rotary drumarranged therein 50' as to form a crescent-shaped workingchambennumerous slidable pistons on said drumarrang'e'd to divide'saidchamber into a ,plurality of cells, said pistons being 10-- cated insubstantially radial slots of the drum, said parts being arranged toprovide I a terminal zone for fluid inlet, a terminal zone for fluidoutlet and an'-1ntermediate working zone, said pistons being sodistributed over the said zones that each zone contains several pistons,a pipe system con-' 'nected to said terminal zones, a controlling valvein said pipe system, a channel -ar ranged to communicate with the innerslot spaces of such pistons that are within one of thesaidterminal zonesas well as with the inner slot space of at least one piston:

within the intermediate working zone, and a pipe connected on the onehand to said channel and onthe other hand to said pipe system beyond itscontrolling valve and adapted to allow preliminary admission of fluidunder pressure to said channel'for starting said machine 'as a motor,substantially as and for the purpose described.

3. Ina rotarymachine, a casing having side walls, a rotary drum arrangedtherein so ;as' to-form a crescent-shaped workingchamber,numerouslslidable pistons on said drumarranged to divide saidchamber into a plurality of cells, said pistons being located insubstantially, radial slots of the drum, said parts being arranged toprovide a terminal zon vior uid inlet, a terminal zone fo'r fluidoutlet-anal an intermediate zworking zone, said pistons being sodistributed over the said three zones that each zone contains severalpistons, a channel in at least one of thesidewalls of thecasing foradmitting flllld to the inner slot spaces of such pistons that arewithin one of the said terminal zones and within the working zone,

an independent channel in the said side wall for-admitting'fluidto theinner slot space of at least one further piston within the working zone,and independent fluid admis sion pipe connections for said channels,substantially as and for the purpose described,

4. In a rotary machine, a casing, a rotary drum arranged therein so asto form a crescent-shaped working ,chamber, numerous slidable pistons onsaid drum arranged to divide said chamber into a plurality of cells,said pistons being located in substantially radial slots of the drum,said parts being arranged to provide a terminal zone for fluid inlet, aterminal zone for fluid outlet and an intermediate working zone, saidpistons being so distributed over the said three zones that each zonecontains several pistons, a channel for admitting fluid to the innerslot spaces of such pistons that are within one terminal zone as well asto the inner slot of at least one piston within the working zone, afluid admission pipe connected to said channel for the admission offluid thereto, and an oil pipe connected to 'said fluid admission pipefor supplying oil thereto in order to use the fluid current passingtherethrough for conveying oil to the aforesaid inner slot spaces forlubricating purposes, substantially as described.

5. Ina rotary machine, the combination of a plurality of elemetarymachines each having a casing, acrotary drum arranged therein so as toform a crescent-shaped working chamber, numerous movable pistons on saiddrum arranged to divide said chamber into a plurality of cells, saidparts being arranged to provide a terminal zone for fluid inlet, aterminal zone for fluid outlet and an intermediate working zone, theworking chambers of two adjacent elementary machines being angularlydisplaced for about 180 degrees from each other, a partition wallbetween the working chambers of two adjacent elementary machines, abearing opening in said partition Wall' and a connection part betweentwo adjacent piston drums tightly guided in said bearing opening and soarranged that the pistons of the drums, when in their outermostposition, have their inner edge inward of the edge of said bearingopening, substantially as and for the purpose described.

'6. In a rotary machine, the combination of a plurality of elementarymachines having each a casing, a rotary drum arranged therein so as toform a crescent-shaped working chamber, numerious movable pistons onsaid drum arranged to divide said chamber into a plurality of cells,said parts being arranged to provide a terminal zone for fluid inlet, aterminal zone for fluid outlet and an intermediate working zone, theworking chambers of two adjacent elementary machines being angularlydisplaced for about 180 degrees from each other, a springpressedpartition wall between the working chambers of two adjacent elementarymachines, said partition wall being slightly movable transversely'to theaxis of the piston drums, a bearing opening in said partition wall and aconnection part between two adjacent piston drums tightly guided in saidbearing opening and so arranged that the pistons of the drums, when intheir outermost position have their inner edges inward of the edge ofsaid bearing opening, substantially as and for the purpose described.

In Witness whereof I have hereunto signed my name/this 2d day ofOctober, 1915, in the presence of two subscribing witnesses.

EMIL WITTIG.

Witnesses ARNOLD ZUBER, AMAND HAusE.

